A mobile communication device (100) includes a receiver (102) which is normally shut off when the mobile communication device is idle. Upon the arrival of a paging time slot to which the mobile communication device is assigned, the mobile communication device turns on the receiver and begins receiving a composite signal including frequency diverse subchannels. The mobile communication device measures the delay spread of the subchannels (406). The receiver then adjusts the receiver on time for the next time slot based on the delay spread of the present time slot.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of reducing receiver power consumption in a mobile communication device while in stand by mode, comprising: powering up the receiver substantially at the start of a first paging channel time slot; receiving a frame of data transmitted during the first paging channel time slot, including receiving a first slot descriptor block in an initial portion of the frame of data, and including receiving a first plurality of frequency diverse subchannels, the subchannels having a plurality of substantially concurrent expected symbols occurring in a plurality of predefined baud intervals of the first slot descriptor block and also occurring on at least two of the frequency diverse subchannels for a given baud interval; performing a plurality of cross correlations of the plurality of substantially concurrent expected symbols occurring on at least two frequency diverse subchannels for each of the plurality of predefined baud intervals and summing the results of the plurality of cross correlations to provide a cross correlation sum; receiving a second slot descriptor block of a second paging channel time slot, wherein the second paging channel time slot is subsequent to the first paging channel time slot; and when the cross correlation sum is above a preselected threshold and the first slot descriptor block indicates there is no more information to receive, terminating reception of the second paging channel time slot after the receiving the second slot descriptor block of the second paging channel time slot, and shutting off the receiver.
2. A method of reducing receiver power consumption as defined in claim 1 , wherein the summing comprises maintaining a separate cross correlation sum for each of : cross correlations performed on subchannels on adjacent frequency bands; cross correlations performed on subchannels separated by one frequency band; and cross correlations performed on subchannels separated by two frequency bands.
3. A method of reducing receiver power consumption as defined in claim 1 , wherein the substantially concurrent expected symbols are pilot symbols.
4. A method of reducing receiver power consumption as defined in claim 1 , wherein the substantially concurrent expected symbols are color code symbols.
5. A method of reducing receiver power consumption as defined in claim 1 , wherein terminating reception of the second paging channel time slot is based on a running average of the first cross correlation sum and at least one previous cross correlation sum of at least one third paging channel time slot, wherein the third paging channel time slot is prior to the first paging channel time slot.
6. A method of reducing receiver power consumption as defined in claim 1 , wherein terminating reception of the second paging channel time slot is based only on the first cross correlation sum.
7. A method of reducing receiver power consumption as defined in claim 1 , wherein the first cross correlation sum determines a second receiver on-time for receiving the second paging channel time slot.
8. A method of operating a mobile communication device, comprising: powering up a receiver of the mobile communication device substantially at the onset of a first channel time slot of a first paging channel time slot assigned to the mobile communication device; receiving a composite signal during the first channel time slot, the composite signal comprised of a plurality of frequency diverse subchannels, the subchannels containing substantially concurrent expected symbols occurring at a plurality of predefined baud intervals of the first channel time slot, each of the substantially concurrent expected symbols occurring on at least two frequency diverse subchannels for a given baud slot; measuring a first fading of the plurality of frequency diverse subchannels by performing a plurality of subchannel fading cross correlations on the substantially concurrent expected symbols occurring on the at least two frequency diverse subchannels for each of the plurality of predefined baud intervals and summing the results of the plurality of subchannel fading cross correlations to provide a cross correlation sum that indicates the first fading; receiving a second channel time slot of the first paging channel time slot, wherein the second channel time slot is subsequent to the first channel time slot; and shutting off the receiver prior to an end of the second channel time slot upon determining the first fading is above a preselected threshold and a second slot descriptor block of the second channel time slot indicates the payload is empty.
9. A method of operating a mobile communication device as defined in claim 8 , wherein the summing comprises maintaining a separate cross correlation sum for each of : cross correlations performed on subchannels on adjacent frequency bands; cross correlations performed on subchannels separated by one frequency band; and cross correlations performed on subchannels separated by two frequency bands.
10. A method of operating a mobile communication device as defined in claim 8 , wherein the concurrent expected symbols are pilot symbols.
11. A method of operating a mobile communication device as defined in claim 8 , wherein the concurrent expected symbols are color code symbols.
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April 9, 2007
March 20, 2012
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